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Re: 96 XP Rec Build

wmazz,
thanks for the tips. Do you think opening up the intake ports like I did will have any positive or negative effect? The sleve openings are about 1mm higher and wider now.
The cylinder exhasut port was smaller than the opening in the sleeve on the sides and bottom and I just blended the cylinder to match the sleeve.IMG_1016[1].JPG

Re: 96 XP Rec Build

Originally Posted by a1965gt

wmazz,
thanks for the tips. Do you think opening up the intake ports like I did will have any positive or negative effect?

I never noticed any difference, and IMO, case porting should be left to
pro engine builder that has a good combo that he sells. The reason I
say that, is that I believe rotary valve timing is already optimized, and
that you may loose performance instead.

Klemm brings up a good point, that the cases are smaller then most
aftermarket carb sets. But in my experience the cases don't create
any problems, or at least, I never noticed any difference on the race
boats. I have ran huge dual 50mm Keihin snowmobile carbs and had
fantastic power without case porting.

I don't recommend you to use such large carbs, or modified carbs like
Buckshot, etc. They can create tuning nightmares, and the potential
for a seizure before you get the engine dialed in.

Re: 96 XP Rec Build

I don't know what you put on the inside of your boat for the sponsons, but you need at least big fender washers like you have on the outside on the sponsons. Backing plates are the preferred method, if you used the small washers in the pic they will pull through in no time.

Re: 96 XP Rec Build

Originally Posted by coldblaster

I don't know what you put on the inside of your boat for the sponsons, but you need at least big fender washers like you have on the outside on the sponsons. Backing plates are the preferred method, if you used the small washers in the pic they will pull through in no time.

Good call on the washers. I picked up some more 1-1/2" fender washers from Ace Hardware. Now the inside washers match the outside.
They should be fine as I pulled the sponsons of an old race boat that only used the 1" washers on the inside.